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  • richardmitnick 8:38 am on May 4, 2019 Permalink | Reply
    Tags: , , , , , Messier 87,   

    From JPL-Caltech: “The Giant Galaxy Around the Giant Black Hole” 

    NASA JPL Banner

    From JPL-Caltech

    1

    The galaxy Messier 87, imaged here by NASA’s Spitzer Space Telescope, is home to a supermassive black hole that spews two jets of material out into space at nearly the speed of light. The inset shows a close-up view of the shockwaves created by the two jets.Credit: NASA/JPL-Caltech/IPAC

    NASA/Spitzer Infrared Telescope

    On April 10, 2019, the Event Horizon Telescope (EHT) unveiled the first-ever image of a black hole’s event horizon, the area beyond which light cannot escape the immense gravity of the black hole.

    The first image of a black hole, Messier 87 Credit Event Horizon Telescope Collaboration, via NSF and ERC 4.10.19

    That giant black hole, with a mass of 6.5 billion Suns, is located in the elliptical galaxy Messier 87. EHT is an international collaboration whose support in the U.S. includes the National Science Foundation.

    This image from NASA’s Spitzer Space Telescope shows the entire M87 galaxy in infrared light. The EHT image, by contrast, relied on light in radio wavelengths and showed the black hole’s shadow against the backdrop of high-energy material around it.

    EHT map

    Located about 55 million light-years from Earth, Messier 87 has been a subject of astronomical study for more than 100 years and has been imaged by many NASA observatories, including the Hubble Space Telescope, the Chandra X-ray Observatory and NuSTAR.

    NASA/ESA Hubble Telescope

    NASA/Chandra X-ray Telescope

    NASA/DTU/ASI NuSTAR X-ray telescope

    In 1918, astronomer Heber Curtis first noticed “a curious straight ray” extending from the galaxy’s center. This bright jet of high-energy material, produced by a disk of material spinning rapidly around the black hole, is visible in multiple wavelengths of light, from radio waves through X-rays. When the particles in the jet impact the interstellar medium (the sparse material filling the space between stars in M87), they create a shockwave that radiates in infrared and radio wavelengths of light but not visible light. In the Spitzer image, the shockwave is more prominent than the jet itself.

    The brighter jet, located to the right of the galaxy’s center, is traveling almost directly toward Earth. Its brightness is amplified due to its high speed in our direction, but even more so because of what scientists call “relativistic effects,” which arise because the material in the jet is traveling near the speed of light. The jet’s trajectory is just slightly offset from our line of sight with respect to the galaxy, so we can still see some of the length of the jet. The shockwave begins around the point where the jet appears to curve down, highlighting the regions where the fast-moving particles are colliding with gas in the galaxy and slowing down.

    The second jet, by contrast, is moving so rapidly away from us that the relativistic effects render it invisible at all wavelengths. But the shockwave it creates in the interstellar medium can still be seen here.

    Located on the left side of the galaxy’s center, the shockwave looks like an inverted letter “C.” While not visible in optical images, the lobe can also be seen in radio waves, as in this image from the National Radio Astronomy Observatory’s Very Large Array.

    Close-up from VLA of a jet near black hole in Messier 87

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    By combining observations in the infrared, radio waves, visible light, X-rays and extremely energetic gamma rays, scientists can study the physics of these powerful jets. Scientists are still striving for a solid theoretical understanding of how gas being pulled into black holes creates outflowing jets.

    Infrared light at wavelengths of 3.6 and 4.5 microns are rendered in blue and green, showing the distribution of stars, while dust features that glow brightly at 8.0 microns are shown in red. The image was taken during Spitzer’s initial “cold” mission.

    The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech.

    More information on Spitzer can be found at its website: http://www.spitzer.caltech.edu/

    See the full article here .


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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL)) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge, on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

    Caltech Logo

    NASA image

     
  • richardmitnick 10:51 am on April 28, 2019 Permalink | Reply
    Tags: , , , , Messier 87, NGC 4258, , Star S0-2 Andrea Ghez Keck/UCLA Galactic Center Group at SGR A*,   

    From Science News: “The M87 black hole image showed the best way to measure black hole masses” 

    From Science News

    April 22, 2019
    Lisa Grossman

    Its diameter suggests the black hole is 6.5 billion times the mass of the sun.

    1
    SUPERMASSIVE SOURCE The gases and stars in galaxy Messier 87, shown in this composite image from the Chandra X-ray telescope and the Very Large Array, gave different numbers for the mass of the galaxy’s supermassive black hole.

    NASA/Chandra X-ray Telescope

    NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    The measure of a black hole is what it does with its stars.

    That’s one lesson astronomers are taking from the first-ever picture of a black hole, released on April 10 by an international telescope team (SN Online: 4/10/19).

    2
    SHADOW SIZE The Event Horizon Telescope captured the first image of M87’s black hole. That image showed that the black hole’s mass is about 6.5 billion times the mass of the sun, close to what astronomers expected based on the galaxy’s stars.

    That image confirmed that the mass of the supermassive black hole in the center of galaxy Messier 87 is close to what astronomers expected from how nearby stars orbit — solving a long-standing debate over how best to measure a black hole’s mass.

    The black hole in Messier 87, which is located about 55 million light-years from Earth, is the first black hole whose mass has been calculated by three precise methods: measuring the motion of stars, the swirl of surrounding gases and now, thanks to the Event Horizon Telescope imaging project, the diameter of the black hole’s shadow.

    EHT map

    In 1978, the first mass estimates to track the motions of stars whipping around the great gravitational center found that the stars must be orbiting something containing about 5 billion times the mass of the sun. A more precise estimate in 2011 using a similar stellar technique bumped its heft up to 6.6 billion times the mass of the sun.

    Star S0-2 Andrea Ghez Keck/UCLA Galactic Center Group at SGR A*, the supermassive black hole at the center of the milky way

    Meanwhile, astronomers in 1994 made another estimate by tracing how gases closer to the black hole than the stars swirl around the behemoth. That technique suggested that the black hole was 2.4 billion solar masses, which was revised in 2013 to 3.5 billion solar masses.

    For years, it wasn’t clear which technique got closer to the truth.

    Now the EHT picture showing a glowing orange ring of gases and dust around the black hole has solved the conflict. According to Einstein’s general theory of relativity, the diameter of the dark space in the center of the image — the black hole’s shadow — is directly related to its mass.

    “Bigger black holes cast bigger shadows,” EHT team member Michael Johnson, an astrophysicist at the Harvard Smithsonian Center for Astrophysics, said April 12 at a talk at MIT. “Easy check, we can see whether one or the other of these [mass measuring methods] is correct.” The shadow of M87’s black hole yielded a diameter of 38 billion kilometers, which let astronomers calculate a mass of 6.5 billion suns [The Astrophysical Journal Letters]— very close to the mass suggested by the motion of stars.

    The size of the shadow also negated the idea that the black hole is a wormhole, a theoretical bridge between distant points in spacetime (SN: 5/31/14, p. 16). If M87’s black hole had been a wormhole, theory predicts it should look smaller than it does. “It’s a stunning confirmation” of general relativity, Johnson said. “We instantly rule out all these exotic possibilities.”

    The mass confirmation may boost confidence in current simulations for how black holes develop, says Priyamvada Natarajan, a Yale University astrophysicist who was not involved with the EHT project. Most black hole mass estimates already use the stellar technique, in part because it’s easier to track a galaxy’s stars from farther away.

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    STARS AND STREAKS Astrophysicists have used both stars and gases to weigh in on the mass of the black hole in the galaxy NGC 4258, shown in this composite image. P.Ogle et al/Caltech/CXC/NASA, R.Gendler, STScI/NASA, Caltech-JPL/NASA, VLA/NRAO/NSF

    SGR A* , the supermassive black hole at the center of the Milky Way. NASA’s Chandra X-Ray Observatory

    Two other black holes whose masses have been measured in multiple ways, the Milky Way’s Sagittarius A* [Astronomy and Astrophysics] and the galaxy NGC 4258’s black hole, also suggest the star method works better. “These three cases now offer renewed faith in our current method,” Natarajan says.

    That faith won’t solve the most pressing black hole problems, such as how black holes grew so big so fast in the early universe — at least not right away (SN Online: 3/16/18). The gas versus star measurement of the M87 black hole mass differed by only a factor of two, which is not enough to explain how it got so massive in the first place. A black hole could double its mass in about a million years, at most.

    “What we don’t know is how we get supermassive black holes within a billion years,” says Hannalore Gerling-Dunsmore, a former Caltech physicist who is joining the University of Colorado Boulder later this year. She was not on the EHT team. “Once you’re already that big, what’s a million years between friends?”

    See the full article here .


    NSF press conference on the EHT Messier 87 Black Hole project


    European Research Council press conference on the EHT Messier 87 Black Hole project


    Katie Bouman on the EHT Messier 87 Black Hole project at Caltech


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  • richardmitnick 2:24 pm on April 27, 2019 Permalink | Reply
    Tags: "Ask Ethan: How Can A Black Hole’s Singularity Spin?", , , , Ethan Siegiel, Messier 87   

    From Ethan Siegel: “Ask Ethan: How Can A Black Hole’s Singularity Spin?” 

    From Ethan Siegel
    Apr 27, 2019

    If a star spins and then collapses, what happens to its angular momentum?

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    An accretion disk, magnetic fields and jets of material are all outside the black hole’s event horizon. Our classical picture of a steady disk, however, only applies to a non-rotating black hole. If you get close to the event horizon itself, rotating, realistic black holes offer some fascinating novel physics for us to consider. (M. WEISS/CFA)

    The most common way to form a black hole in the Universe is to have a massive star reach the end of its life and explode in a catastrophic supernova. However, while the outside portions of the star are blown apart, the inner core collapses, forming a black hole if the progenitor star is massive enough. But most real stars, including our Sun, are spinning. Therefore — since angular momentum is always conserved — they shouldn’t be able to collapse down to a single point. How does this all work? That’s what our Patreon supporter Aaron Weiss wants to know, asking:

    How [is] angular momentum conserved when stars collapse to black holes? What [does] it means for a black hole to spin? What is actually spinning? How can a singularity spin? Is there a “speed limit” to this spin rate and how does the spin affect the size of the event horizon and the area immediately around it?

    These are all good questions. Let’s find out.

    2
    The gravitational behavior of the Earth around the Sun is not due to an invisible gravitational pull, but is better described by the Earth falling freely through curved space dominated by the Sun. The shortest distance between two points isn’t a straight line, but rather a geodesic: a curved line that’s defined by the gravitational deformation of spacetime. (LIGO/T. PYLE)

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    In a Universe that isn’t expanding, you can fill it with stationary matter in any configuration you like, but it will always collapse down to a black hole. Such a Universe is unstable in the context of Einstein’s gravity, and must be expanding to be stable, or we must accept its inevitable fate. (E. SIEGEL / BEYOND THE GALAXY)

    Once you get matter with a sufficient amount of mass confined to a small enough volume, an event horizon will form at a particular location. A spherical region of space, whose radius is defined by the quantity of mass inside of it, will experience such severe curvature that anything passing interior to its boundary will be unable to escape.

    Outside of this event horizon, it will appear as though there is just an extreme region where gravity is very intense, but no light or matter can be emitted from within it. To anything that falls inside, however, it inevitably gets brought towards the very center of this black hole: towards a singularity. While the laws of physics break down at this point — some physicists cheekily refer to singularities as places where “God divided by zero” — no one doubts that all the matter and radiation that passes inside the event horizon heads towards this point-like region of space.

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    An illustration of heavily curved spacetime, outside the event horizon of a black hole. As you get closer and closer to the mass’s location, space becomes more severely curved, eventually leading to a location from within which even light cannot escape: the event horizon. The radius of that location is set by the mass of the black hole, the speed of light, and the laws of General Relativity alone. In theory, there should be a special point, a singularity, where all the mass is concentrated for stationary, spherically-symmetric black holes. (PIXABAY USER JOHNSONMARTIN)

    I can hear the objections already. After all, there are a legitimate number of ways the actual Universe works differently from this naive picture of gravitational collapse.

    The gravitational force isn’t the only one in the Universe: nuclear forces and electromagnetism play a role when it comes to matter and energy, too.
    Black holes aren’t formed from the collapse of a uniform distribution of matter, but rather by the implosion of a massive star’s core when nuclear fusion can no longer continue.
    And, perhaps most importantly, all stars we’ve ever discovered spin, and angular momentum is always conserved, so black holes should be spinning, too.

    So let’s do it: let’s go from the realm of a simplistic approximation to a more realistic picture of how black holes truly work.

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    In 2006, Mercury transited across the Sun, but the large sunspot visible on the Sun’s disk actually reduced its light output by a greater factor. By observing the locations of sunspots moving over time, we have determined that the Sun exhibits differential rotation, with the equator and poles taking anywhere from 25 to 33 Earth days to make a complete revolution. (WILLIAMS COLLEGE; GLENN SCHNEIDER, JAY PASACHOFF, AND SURANJIT TILAKAWARDANE)

    All stars spin. Our Sun, a relatively slow rotator, completes a full 360° turn on timescales ranging from 25 to 33 days, depending on which particular solar latitude you’re monitoring. But our Sun is huge and very low-density, and there are far more extreme objects in the Universe in terms of small physical sizes and large masses. Just as a spinning figure skater speeds up when they bring their arms and legs in, astrophysical masses rotate more quickly if you decrease their radius.

    If the Sun were a white dwarf — with the same mass but the physical size of Earth — it would rotate once every 4 minutes.

    If it became a neutron star — with the same mass but a radius of 20 km — it would rotate once every 2.4 milliseconds: consistent with what we observe for the fastest pulsars.

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    A neutron star is one of the densest collections of matter in the Universe, but there is an upper limit to their mass. Exceed it, and the neutron star will further collapse to form a black hole. The fastest-spinning neutron star we’ve ever discovered is a pulsar that revolves 766 times per second: faster than our Sun would spin if we collapsed it down to the size of a neutron star. (ESO/LUÍS CALÇADA)

    Well, if our star (or any star) collapsed down to a black hole, we’d still have to conserve angular momentum. When something spins in this Universe, there’s no way to just get rid of it, the same way you can’t create or destroy energy or momentum. It has to go somewhere. When any collection of matter collapses down to a radius smaller than the radius of an event horizon, that angular momentum is trapped inside there, too.

    This is okay! Einstein put forth his theory of General Relativity in 1915, and it was only a few months later that Karl Schwarzschild found the first exact solution: for a point mass, the same as a spherical black hole. The next step in modeling this problem in a more realistic fashion — to consider what if the black hole also has angular momentum, instead of mass alone — wasn’t solved until Roy Kerr found the exact solution in 1963.

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    The exact solution for a black hole with both mass and angular momentum was found by Roy Kerr in 1963. It revealed, instead of a single event horizon with a point-like singularity, an inner and outer event horizon, as well as an inner and outer ergosphere, plus a ring-like singularity of substantial radius. (MATT VISSER, ARXIV:0706.0622)

    There are some fundamental and important differences between the more naive, simpler Schwarzschild solution and the more realistic, complex Kerr solution. In no particular order, here are some fascinating contrasts:

    1.Instead of a single solution for where the event horizon is, a rotating black hole has two mathematical solutions: an inner and and outer event horizon.
    2.Outside of even the outer event horizon, there is a place known as the ergosphere, where space itself is dragged around at a rotational speed equal to the speed of light, and particles falling in there experience enormous accelerations.
    3.There is a maximum ratio of angular momentum to mass that is allowed; if there is too much angular momentum, the black hole will radiate that energy away (via gravitational radiation) until it’s below that limit.
    4.And, perhaps most fascinatingly, the singularity at the black hole’s center is no longer a point, but rather a 1-dimensional ring, where the radius of the ring is determined by the mass and angular momentum of the black hole.

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    The visible/near-IR photos from Hubble show a massive star, about 25 times the mass of the Sun, that has winked out of existence, with no supernova or other explanation. Direct collapse is the only reasonable candidate explanation, and is one known way, in addition to supernovae or neutron star mergers, to form a black hole. (NASA/ESA/C. KOCHANEK (OSU))

    All of this is true for a rotating black hole from the instant you create the event horizon for the first time. A high-mass star can go supernova, where the spinning core implodes and collapses down to a black hole, and all of this will be true. In fact, there is even some hope that if a supernova goes off in our own local group, LIGO might be able to detect the gravitational waves from a rapidly rotating black hole’s ring down.

    If you form a black hole from a neutron star-neutron star merger or the direct collapse of a star or gas cloud, the same possibilities hold true. But once your black hole exists, its angular momentum can constantly change as new matter or material falls in. The size of the event horizon can grow, and the size of the singularity and ergosphere can grow or shrink depending on the angular momentum of the new material that gets added.

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    Due to the properties of the rotating, dragged space near a realistic black hole with angular momentum, individual particles that would form planar orbits around non-rotating masses wind up occupying a large, torus-like shape in three dimensions. (MAARTEN VAN DE MEENT / WIKIMEDIA COMMONS)

    This leads to some fascinating behavior that you might not expect. In the case of a non-rotating black hole, a particle of matter outside of it can orbit, escape, or fall inside, but will remain in the same plane. When a black hole rotates, however, it gets dragged around through all three dimensions, where it will fill a torus-like region surrounding the black hole’s equator.

    There’s also an important distinction between a mathematical solution and a physical solution. If I told you I had the (square root of 4) oranges, you would conclude that I had 2 oranges. You could have just as easily concluded, mathematically, that I had -2 oranges, because the square root of 4 could just as easily be -2 as it could be +2. But in physics, there’s only one meaningful solution. As scientists have long noted, though:

    ” …you should not physically trust in the inner horizon or the inner ergosurface. Although they are certainly there as mathematical solutions of the exact vacuum Einstein equations, there are good physics reasons to suspect that the region at and inside the inner horizon, which can be shown to be a Cauchy horizon, is grossly unstable — even classically — and unlikely to form in any real astrophysical collapse.”

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    Shadow (black) & horizons and ergospheres (white) of a rotating black hole. The quantity of a, shown varying in the image, has to do with the relationship of angular momentum of the black hole to its mass. Note that the shadow as seen by the Event Horizon Telescope of the black hole is much larger than either the event horizon or ergosphere of the black hole itself. (YUKTEREZ (SIMON TYRAN, VIENNA) / WIKIMEDIA COMMONS)

    Now that we’ve finally observed a black hole’s event horizon for the first time, owing to the incredible success of the Event Horizon Telescope [EHT], scientists have been able to compare their observations with theoretical predictions. By running a variety of simulations detailing what the signals of black holes with various masses, spins, orientations, and accreting matter flows would be, they’ve been able to come up with the best fit for what they saw. Although there are some substantial uncertainties, the black hole at the center of M87 appears to be:

    rotating at 94% of its maximum speed,
    with a 1-dimensional ring singularity with a diameter of ~118 AU (larger than Pluto’s orbit),
    with its rotational axis pointing away from Earth at ~17°,
    and that all of the observations are consistent with a Kerr (which is favored over a Schwarzschild) black hole.

    The first image of a black hole, Messier 87 Credit Event Horizon Telescope Collaboration, via NSF 4.10.19

    In April of 2017, all 8 of the telescopes/telescope arrays associated with the Event Horizon Telescope pointed at Messier 87. This is what a supermassive black hole looks like, where the event horizon is clearly visible.

    EHT map

    Only through VLBI could we achieve the resolution necessary to construct an image like this, but the potential exists to someday improve it by a factor of hundreds. The shadow is consistent with a rotating (Kerr) black hole. (EVENT HORIZON TELESCOPE COLLABORATION ET AL.)

    Perhaps the most profound takeaway from all of this, though, is that in a rotating spacetime, space itself can indeed move without any sort of speed limit at all. It’s only the motion of matter and energy through space that’s limited by the speed of light; space itself has no such speed limit. In the case of a rotating black hole, there is a region of space beyond the event horizon where space is dragged around the black hole at a speed faster than the speed of light, and this is just fine. Matter still cannot move through that space at speeds exceeding the ultimate cosmic speed limit, and all of this is consistent with both relativity and what we observe.

    As more black holes are imaged and more and improved observations come in, we fully expect to learn even more about the physics of real, spinning black holes. But until then, know that our theory and observation are guiding us in a direction that’s tremendously profound, self-consistent, and — above all — the best approximation of reality that we currently have.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
  • richardmitnick 1:12 pm on April 13, 2019 Permalink | Reply
    Tags: "When a Black Hole Finally Reveals Itself, , It Helps to Have Our Very Own Cosmic Reporter", Messier 87,   

    From The New York Times: “When a Black Hole Finally Reveals Itself, It Helps to Have Our Very Own Cosmic Reporter” 

    New York Times

    From The New York Times

    April 12, 2019
    Aidan Gardiner

    Astronomers announced Wednesday that they had captured the first image of a black hole. The Times’s Dennis Overbye answers readers’ questions.

    2
    The first image of a black hole, from the galaxy Messier 87.Credit Event Horizon Telescope Collaboration, via National Science Foundation

    1
    Dennis Overbye, cosmic reporter for The New York Times, answering readers’ questions at his desk.Credit Aidan Gardiner/The New York Times

    When radio waves from the depths of a nearby galaxy known as Messier 87 traveled some 55 million light-years to a constellation of telescopes on Earth, revealing to humanity the face of a black hole for the first time, people around the planet paused in wonder.

    Why does it look like a doughnut? How scary is it when two of these things smash into each other? And if light can’t escape a black hole, what are we even looking at?

    Our coverage Wednesday of the first ever image of a black hole, by our cosmic reporter Dennis Overbye, drew a huge response from our readers. Dennis graduated from M.I.T. with a physics degree and was a Pulitzer Prize finalist in 2014 for his coverage for The New York Times of the race to find the Higgs boson. He sat down Thursday with his feet on his desk, beside a photo of the black hole, to answer some of our readers’ questions and respond to their feedback.

    Below are some of the exchanges that he had during an AMA on Reddit and in the comments on his article. They are edited for clarity.

    What does this image really tell us besides black holes are round?

    This is the first look into the central engine that generates the enormous energies put out by quasars, radio galaxies and other so-called active galactic nuclei. The action all starts down at the edge of oblivion, in a maelstrom of hot gas, gravity, magnetic fields and otherworldly pressures. It extends out beyond the far reaches of the galaxy, as jets of radio-wave energy moving at nearly the speed of light; these lobes of radio energy can accompany shock waves capable of blowing the gas out of galaxies or even entire clusters of them, preventing stars from forming. Through these mechanisms, black holes, blowing hot and cold, control the growth and structure of galaxies. It all starts in the accretion disk, the doughnut of doom.

    Why does it look like a “doughnut of doom” and not a sphere?

    When matter falls together into a black hole, or in almost any other situation, it has angular momentum, and takes on the shape of a flattened pancake spinning around the central attraction. Also, the black hole is probably spinning, pulling the disk around in the same direction. We are seeing the disk almost directly face-on, so it looks like a doughnut hole. (From edge-on it would look different.) Bent by gravity, light wraps around the hole on its way to our eyes, so the black hole magnifies and distorts the image of the accretion disk.

    Will we ever get a clearer image of this black hole?

    We will. The key is to observe black holes at shorter and shorter radio wavelengths, which allows more and more detail to be resolved. The latest images were recorded at a wavelength of 1.3 millimeters in the microwave band. The Event Horizon team hopes to go to shorter wavelengths in the future, and to use more antennas, including one in space, which would increase the size of their “virtual telescope” and also increase resolution.

    Do you feel that coverage of the breakthrough minimized the role of Katherine Bouman, a researcher at the Harvard-Smithsonian Center for Astrophysics?

    The issue of the unsung hero or heroine is a big problem, especially in Big Science, which the Event Horizon Telescope is surely part of.

    There were 207 people in the collaboration, according to one of the physicists I talked to that day. I am sure that many crucial contributions and rich anecdotes of behind-the-scenes science got missed.

    In time, these will come out in more thoughtful, longer narratives. On the day of the announcement there was a tsunami of information released at 9 a.m., and a rush to post stories as soon as possible, an unfortunate fact of the internet age.

    What does current science tell us is supposed to happen in the gravitational extremes of a black hole?

    That’s the biggie everybody wants to know. Whatever happens there, it probably is similar to what happened, maybe in reverse, in the Big Bang. Space, time, matter all go away, replaced by what? Some people think the answers might come from string theory, which unites gravity with quantum theory. But for now it remains an untestable, but mathematically elegant, speculation.

    What happens when two black holes collide?

    Such collisions have happened and been recorded by the LIGO gravitational wave observatory.


    They vibrated the space-time continuum like a drum and released as much energy in a fraction of a second as all the stars in the observable universe. The result in each case was an even bigger, blended black hole.

    But outside the event horizon, the gravitational field of a black hole is just like that of a star and it is no more dangerous. Black holes don’t go roaming around looking to swallow you. They only hurt if you touch them, in which case you won’t ever be able to let go. Otherwise they are like any other animal that you would just let go, and mind your own business.

    How is any of this relevant to our day-to-day lives?

    It can certainly provide context to your daily life, but it won’t move the markets. It will, or could, move your soul. However, Einstein, when he invented the sort of trampoline universe described by general relativity, did not dream that it would lead to pocket devices that keep time and tell you precisely where you are on Earth — that is to say, GPS. But they depend crucially on general relativity to tell you where you are. So who knows?

    See the full article here .

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  • richardmitnick 6:10 pm on April 11, 2019 Permalink | Reply
    Tags: , , , , , Messier 87, , , , ,   

    From Nautilus: “First Black-Hole Image: It’s Not Looks That Count” 

    Nautilus

    From Nautilus

    Apr 11, 2019
    Sabine Hossenfelder

    1
    FIRST LOOK: The Event Horizon Telescope measures wavelength in the millimeter regime, too long to be seen by eye, but ideally suited to the task of imaging a black hole: The gas surrounding the black hole is almost transparent at this wavelength and the light travels to Earth almost undisturbed. Since we cannot see light of such wavelength by eye, the released telescope image shows the observed signal shifted into the visible range.Event Horizon Telescope Collaboration.

    “The Day Feynman Worked Out Black-Hole Radiation on My Blackboard”
    2
    After a few minutes, Richard Feynman had worked out the process of spontaneous emission, which is what Stephen Hawking became famous for a year later.Wikicommons.

    The Italian 14th-century painter, Giotto di Bondone, when asked by the Pope to prove his talent, is said to have swung his arm and drawn a perfect circle. But geometric perfection is limited by the medium. Inspect a canvas closely enough, and every circle will eventually appear grainy. If perfection is what you seek, don’t look at man-made art, look at the sky. More precisely, look at a black hole.

    Looking at a black hole is what the Event Horizon Telescope has done for the past 12 years. Yesterday, the collaboration released the long-awaited results from its first full run in April 2017. Contrary to expectation, their inaugural image is not, as many expected, Sagittarius A*, the black hole at the center of the Milky Way. Instead, it is the supermassive black hole in the elliptic galaxy Messier 87, about 55 million light-years from here. This black hole weighs in at 6.5 billion times the mass of our sun, and is considerably larger than the black hole in our own galaxy [1,000 times the size of SGR A*]. So, even though the Messier 87 black hole is a thousand times farther away than Sagittarius A*, it still appears half the size in the sky.

    The Event Horizon Telescope (EHT) is not less remarkable than the objects it observes. With a collaboration of 200 people, the EHT uses not a single telescope, but a global network of nine telescopes. Its sites, from Greenland to the South Pole and from Hawaii to the French Alps, act in concert as one. Together, the collaboration commands a telescope the size of planet Earth, staring at a tiny patch in the northern sky that contains the Messier-87 black hole.

    Event Horizon Telescope Array

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada,, Altitude 2,850 m (9,350 ft)


    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile [recently added]

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL [recently added]

    Future Array/Telescopes

    NOEMA (NOrthern Extended Millimeter Array) will double the number of its 15 meter antennas of its predecessor from six to twelve, located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters

    NSF CfA Greenland telescope


    Greenland Telescope

    ARO 12m Radio Telescope, Kitt Peak National Observatory, Arizona, USA, Altitude 1,914 m (6,280 ft)


    ARO 12m Radio Telescope

    In theory, black holes are regions of space where the gravitational pull is so large that everything, including light, becomes trapped for eternity. The surface of the trapping region is called the “event horizon.” It has no substance; it is a property of space itself. In the simplest case, the event horizon is a sphere—a perfect sphere, made of nothing.

    In reality, it’s complicated. Astrophysicists have had evidence for the existence of black holes since the 1990s, but so far all observations have been indirect—inferred from the motion of visible stars and gas, leaving doubt as to whether the dark object really possesses the defining event horizon. It turned out difficult to actually see a black hole. Trouble is, they’re black. They trap light. And while Stephen Hawking proved that black holes must emit radiation due to quantum effects, this quantum glow is far too feeble to observe.

    But much like the prisoners in Plato’s cave, we can see black holes by observing the shadows they cast. Black holes attract gas from their environment. This gas collects in a spinning disk, and heats up as it spirals into the event horizon, pushing around electric charges. This gives rise to strong magnetic fields that can create a “jet,” a narrow, directed stream of particles leaving the black hole at almost the speed of light. But whatever strays too close to the event horizon falls in and vanishes without a trace.

    At the same time black holes bend rays of light, bend them so strongly, indeed, that looking at the front of a black hole, we can see part of the disk behind it. The light that just about manages to escape reveals what happens nearby the horizon. It is an asymmetric image that the astrophysicists expect, brighter on the side of the black hole where the material surrounding it moves toward us, and darker where it moves away from us. The hot gas combined with the gravitational lensing creates the unique observable signature that the EHT looks out for.

    The experimental challenge is formidable. The network’s telescopes must synchronize their data-taking using atomic clocks. Weather conditions must be favorable at all locations simultaneously. Once recorded, the amount of data is so staggeringly large, it must be shipped on hard disks to central locations for processing.

    The theoretical challenges are not any lesser. Black holes bend light so much that it can wrap around the horizon multiple times. The resulting image is too complicated to capture in simple equations. Though the math had been known since the 1920s, it wasn’t until 1978 that physicists got a first glimpse of what a black hole would actually look like. In that year, the French astrophysicist Jean-Pierre Luminet programmed the calculation on an IBM 7040 using punchcards. He drew the image by hand.

    Today, astrophysicists use computers many times more powerful to predict the accretion of gas onto the black hole and how the light bends before reaching us. Still, the partly turbulent motion of the gas, the electric and magnetic fields created by it, and the intricacies of the particle’s interactions are not fully understood.

    The EHT’s observations agree with expectation. But this result is more than just another triumph of Einstein’s theory of general relativity. It is also a triumph of the astronomers’ resourcefulness. They joined hands and brains to achieve what they could not have done separately. And while their measurement settles a long-standing question—yes, black holes really do have event horizons!—it is also the start of further exploration. Physicists hope that the observations will help them understand better the extreme conditions in the accretion disk, the role of magnetic fields in jet formation, and the way supermassive black holes affect galaxy formation.

    When the Pope received Giotto’s circle, it was not the image itself that impressed him. It was the courtier’s report that the artist produced it without the aid of a compass. This first image of a black hole, too, is remarkable not so much for its appearance, but for its origin. A black sphere, spanning 40 billion kilometers, drawn on a background of hot gas by the greatest artist of all: Nature herself.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

     
  • richardmitnick 10:08 am on April 10, 2019 Permalink | Reply
    Tags: , Although the telescopes are not physically connected they are able to synchronize their recorded data with atomic clocks — hydrogen masers — which precisely time their observations., , , , BlackHoleCam, , Data were flown to highly specialised supercomputers — known as correlators — at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined., , , Messier 87, Sagittarius A* the supermassive black hole at the center of our galaxy, VLBI-very-long-baseline interferometry   

    From European Southern Observatory: “Astronomers Capture First Image of a Black Hole” 

    ESO 50 Large

    From European Southern Observatory

    10 April 2019

    Heino Falcke
    Chair of the EHT Science Council, Radboud University
    The Netherlands
    Tel: +31 24 3652020
    Email: h.falcke@astro.ru.nl

    Luciano Rezzolla
    EHT Board Member, Goethe Universität
    Germany
    Tel: +49 69 79847871
    Email: rezzolla@itp.uni-frankfurt.de

    Eduardo Ros
    EHT Board Secretary, Max-Planck-Institut für Radioastronomie
    Germany
    Tel: +49 22 8525125
    Email: ros@mpifr.de

    Calum Turner
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Email: pio@eso.org

    ESO, ALMA, and APEX contribute to paradigm-shifting observations of the gargantuan black hole at the heart of the galaxy Messier 87.

    1
    The Event Horizon Telescope (EHT) — a planet-scale array of eight ground-based radio telescopes forged through international collaboration — was designed to capture images of a black hole. Today, in coordinated press conferences across the globe, EHT researchers reveal that they have succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow.

    This breakthrough was announced today in a series of six papers published in a special issue of The Astrophysical Journal Letters. The image reveals the black hole at the centre of Messier 87 [1], a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides 55 million light-years from Earth and has a mass 6.5 billion times that of the Sun [2].

    The EHT links telescopes around the globe to form an unprecedented Earth-sized virtual telescope [3]. The EHT offers scientists a new way to study the most extreme objects in the Universe predicted by Einstein’s general relativity during the centenary year of the historic experiment that first confirmed the theory [4].

    “We have taken the first picture of a black hole,” said EHT project director Sheperd S. Doeleman of the Center for Astrophysics | Harvard & Smithsonian. “This is an extraordinary scientific feat accomplished by a team of more than 200 researchers.”

    Black holes are extraordinary cosmic objects with enormous masses but extremely compact sizes. The presence of these objects affects their environment in extreme ways, warping spacetime and superheating any surrounding material.

    “If immersed in a bright region, like a disc of glowing gas, we expect a black hole to create a dark region similar to a shadow — something predicted by Einstein’s general relativity that we’ve never seen before,” explained chair of the EHT Science Council Heino Falcke of Radboud University, the Netherlands. “This shadow, caused by the gravitational bending and capture of light by the event horizon, reveals a lot about the nature of these fascinating objects and has allowed us to measure the enormous mass of Messier 87’s black hole.”

    Multiple calibration and imaging methods have revealed a ring-like structure with a dark central region — the black hole’s shadow — that persisted over multiple independent EHT observations.

    “Once we were sure we had imaged the shadow, we could compare our observations to extensive computer models that include the physics of warped space, superheated matter and strong magnetic fields. Many of the features of the observed image match our theoretical understanding surprisingly well,” remarks Paul T.P. Ho, EHT Board member and Director of the East Asian Observatory [5]. “This makes us confident about the interpretation of our observations, including our estimation of the black hole’s mass.”

    “The confrontation of theory with observations is always a dramatic moment for a theorist. It was a relief and a source of pride to realise that the observations matched our predictions so well,” elaborated EHT Board member Luciano Rezzolla of Goethe Universität, Germany.

    Creating the EHT was a formidable challenge which required upgrading and connecting a worldwide network of eight pre-existing telescopes deployed at a variety of challenging high-altitude sites. These locations included volcanoes in Hawai`i and Mexico, mountains in Arizona and the Spanish Sierra Nevada, the Chilean Atacama Desert, and Antarctica.

    The EHT observations use a technique called very-long-baseline interferometry (VLBI) which synchronises telescope facilities around the world and exploits the rotation of our planet to form one huge, Earth-size telescope observing at a wavelength of 1.3mm. VLBI allows the EHT to achieve an angular resolution of 20 micro-arcseconds — enough to read a newspaper in New York from a café in Paris [6].

    The telescopes contributing to this result were ALMA, APEX, the IRAM 30-meter telescope, the James Clerk Maxwell Telescope, the Large Millimeter Telescope Alfonso Serrano, the Submillimeter Array, the Submillimeter Telescope, and the South Pole Telescope [7]. Petabytes of raw data from the telescopes were combined by highly specialised supercomputers hosted by the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory.

    Max Planck Institute for Radio Astronomy Bonn Germany

    MIT Haystack Observatory, Westford, Massachusetts, USA, Altitude 131 m (430 ft)

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)

    IRAM 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada,, Altitude 2,850 m (9,350 ft)

    East Asia Observatory James Clerk Maxwell telescope, Mauna Kea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    The University of Massachusetts Amherst and Mexico’s Instituto Nacional de Astrofísica, Óptica y Electrónica
    Large Millimeter Telescope Alfonso Serrano, Mexico, at an altitude of 4850 meters on top of the Sierra Negra

    CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

    U Arizona Submillimeter Telescope located on Mt. Graham near Safford, Arizona, USA, Altitude 3,191 m (10,469 ft)

    South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including the University of Chicago, the University of California, Berkeley, Case Western Reserve University, Harvard/Smithsonian Astrophysical Observatory, the University of Colorado Boulder, McGill University, The University of Illinois at Urbana-Champaign, University of California, Davis, Ludwig Maximilian University of Munich, Argonne National Laboratory, and the National Institute for Standards and Technology. It is funded by the National Science Foundation. Altitude 2.8 km (9,200 ft)

    European facilities and funding played a crucial role in this worldwide effort, with the participation of advanced European telescopes and the support from the European Research Council — particularly a €14 million grant for the BlackHoleCam project [8]. Support from ESO, IRAM and the Max Planck Society was also key. “This result builds on decades of European expertise in millimetre astronomy”, commented Karl Schuster, Director of IRAM and member of the EHT Board.

    The construction of the EHT and the observations announced today represent the culmination of decades of observational, technical, and theoretical work. This example of global teamwork required close collaboration by researchers from around the world. Thirteen partner institutions worked together to create the EHT, using both pre-existing infrastructure and support from a variety of agencies. Key funding was provided by the US National Science Foundation (NSF), the EU’s European Research Council (ERC), and funding agencies in East Asia.

    “ESO is delighted to have significantly contributed to this result through its European leadership and pivotal role in two of the EHT’s component telescopes, located in Chile — ALMA and APEX,” commented ESO Director General Xavier Barcons. “ALMA is the most sensitive facility in the EHT, and its 66 high-precision antennas were critical in making the EHT a success.”

    “We have achieved something presumed to be impossible just a generation ago,” concluded Doeleman. “Breakthroughs in technology, connections between the world’s best radio observatories, and innovative algorithms all came together to open an entirely new window on black holes and the event horizon.”
    Notes

    [1] The shadow of a black hole is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape. The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across.

    [2] Supermassive black holes are relatively tiny astronomical objects — which has made them impossible to directly observe until now. As the size of a black hole’s event horizon is proportional to its mass, the more massive a black hole, the larger the shadow. Thanks to its enormous mass and relative proximity, M87’s black hole was predicted to be one of the largest viewable from Earth — making it a perfect target for the EHT.

    [3] Although the telescopes are not physically connected, they are able to synchronize their recorded data with atomic clocks — hydrogen masers — which precisely time their observations. These observations were collected at a wavelength of 1.3 mm during a 2017 global campaign. Each telescope of the EHT produced enormous amounts of data – roughly 350 terabytes per day – which was stored on high-performance helium-filled hard drives. These data were flown to highly specialised supercomputers — known as correlators — at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined. They were then painstakingly converted into an image using novel computational tools developed by the collaboration.

    [4] 100 years ago, two expeditions set out for Principe Island off the coast of Africa and Sobral in Brazil to observe the 1919 solar eclipse, with the goal of testing general relativity by seeing if starlight would be bent around the limb of the sun, as predicted by Einstein. In an echo of those observations, the EHT has sent team members to some of the world’s highest and most isolated radio facilities to once again test our understanding of gravity.

    [5] The East Asian Observatory (EAO) partner on the EHT project represents the participation of many regions in Asia, including China, Japan, Korea, Taiwan, Vietnam, Thailand, Malaysia, India and Indonesia.

    [6] Future EHT observations will see substantially increased sensitivity with the participation of the IRAM NOEMA Observatory, the Greenland Telescope and the Kitt Peak Telescope.

    [7] ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences(NINS) of Japan, together with the National Research Council (Canada), the Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. APEX is operated by ESO, the 30-meter telescope is operated by IRAM (the IRAM Partner Organizations are MPG (Germany), CNRS (France) and IGN (Spain)), the James Clerk Maxwell Telescope is operated by the EAO, the Large Millimeter Telescope Alfonso Serrano is operated by INAOE and UMass, the Submillimeter Array is operated by SAO and ASIAA and the Submillimeter Telescope is operated by the Arizona Radio Observatory (ARO). The South Pole Telescope is operated by the University of Chicago with specialized EHT instrumentation provided by the University of Arizona.

    [8] BlackHoleCam is an EU-funded project to image, measure and understand astrophysical black holes. The main goal of BlackHoleCam and the Event Horizon Telescope (EHT) is to make the first ever images of the billion solar masses black hole in the nearby galaxy Messier 87 and of its smaller cousin, Sagittarius A*, the supermassive black hole at the centre of our Milky Way. This allows the determination of the deformation of spacetime caused by a black hole with extreme precision.

    More information

    This research was presented in a series of six papers published today in a special issue of The Astrophysical Journal Letters.

    The EHT collaboration involves more than 200 researchers from Africa, Asia, Europe, North and South America. The international collaboration is working to capture the most detailed black hole images ever by creating a virtual Earth-sized telescope. Supported by considerable international investment, the EHT links existing telescopes using novel systems — creating a fundamentally new instrument with the highest angular resolving power that has yet been achieved.

    The EHT consortium consists of 13 stakeholder institutes; the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe-Universitaet Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max Planck Institute for Radio Astronomy, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University and the Smithsonian Astrophysical Observatory.

    Links

    ESO EHT web page
    EHT Website & Press Release
    ESOBlog on the EHT Project

    Papers:

    Paper I: The Shadow of the Supermassive Black Hole
    Paper II: Array and Instrumentation
    Paper III: Data processing and Calibration
    Paper IV: Imaging the Central Supermassive Black Hole
    Paper V: Physical Origin of the Asymmetric Ring
    Paper VI: The Shadow and Mass of the Central Black Hole

    See the full article here .


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    Visit ESO in Social Media-

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre EEuropean Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

     
  • richardmitnick 10:04 am on August 22, 2018 Permalink | Reply
    Tags: , , , , , , Messier 87,   

    From Instituto de Astrofísica de Canarias – IAC via Manu Garcia: “Discover the causes of the apparent displacement of a supermassive black hole” 


    From Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    IAC

    From Instituto de Astrofísica de Canarias – IAC

    Observing the core of Messier 87, HST-1 galaxy.

    1
    Messier 87 image with WFC3 HST (2016) with F814W filter. different knots are seen along the jet, including the first node HST-1. Credit: NASA/ESA Hubble.

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble WFC3

    The study by two researchers from Instituto de Astrofísica reveals that the shift observed in the nucleus of the galaxy Messier 87 is not due to a shift of its massive black hole, but variations in light production in the center of the galaxy caused by bursts from a jet, a flow of material relativistic beam as the hole itself emits.

    Today it is assumed that all massive galaxies contain a supermassive black hole (SMBH, for its acronym in English) at its core. In recent years galaxies are looking for candidates to present a SMBHs displaced from its equilibrium position. Among the scenarios that can cause this displacement are merging two SMBHs or the existence of a binary system SMBHs, which gives information about galactic evolution and formation frequency and fusion of such objects.

    One of the galaxies candidates to present a displaced SMBHs is the giant elliptical Messier 87, containing one of the closest and best-studied active galaxy nuclei (AGN, for its acronym in English). Previous research SMBHs displacement of Messier 87 gave very different results, which was confusing. However, a new study by the student of the University of La Laguna (ULL), Elena López Navas has provided new data suggesting that the SMBHs of this galaxy is in its equilibrium position and shifts found must be variations in the production center or photocentric light caused by bursts from the relativistic jet, a flow of matter that the hole itself expelled outside at speeds near that of light.

    Research has been necessary to analyze a large number of high-resolution images of Messier 87 taken at different times and with different instruments installed on the Hubble Space Telescope (HST) and the Very Large Telescope (VLT).

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo

    “Given these results, we realized that the images showed a shift in the center of the galaxy were taken at a time when M87 was a huge explosion that could be measured in all ranges of the electromagnetic spectrum,” adds Almudena Prieto , co-author and researcher at the Institute of Astrophysics of the Canary Islands (IAC). This outbreak took place between 2003 and 2007 at the node nearest the nucleus known as Messier 87 HST-1 jet. During the duration of the phenomenon, this knot increased its flow coming to shine even more than the core itself. “Temporal analysis of displacement of center of the galaxy shows that indeed the burst is related to the change of the position of photocentric – clarifies the astrophysics, however, after this phenomenon, and the core photocentric meet occupying the same place, so we deduce that the core and the black hole are always in the same location coinciding with the minimum of galactic potential. ”

    2
    Displacements found (in milli – arcseconds) against the date of
    observation of each analyzed image. An increase of displacement is observed
    around 2005, when the maximum emission occurred in the first
    knot jet, HST-1. Credit: Elena Lopez.

    “In our work we have found that the SMBHs is in a stable over the last 20 years position; On the contrary, what changes is the production center of light or Fotocentro “says Lopez, author of this study, as work Master’s Research in Astrophysics, which has just been published in the journal <em>Monthly Notices of the Royal Astronomical Society</em> (MNRAS).

    The new data have caused great interest among the astrophysics community, as the study SMBHs position of M87 is crucial to understanding the evolution of this galaxy and analysis of other AGN jets. “In addition, this research reminds us that we must be cautious when considering variables sources with irregularities such as, in this case, a huge jet,” says Lopez, who is currently conducting a training grant in astrophysical research at the IAC.

    Work Master Thesis: E. Lopez Navas (2018 ULL), “Measurement and analysis of the displacement between the Fotocentro and the supermassive black hole in M87“.

    Contact:
    Elena Lopez Navas, ULL student / IAC: eln_ext@iac.es
    Almudena Prieto Escudero, a researcher at the IAC: aprieto@iac.es

    See the full article here.


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    The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

    The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
    The Centro de Astrofísica en La Palma (CALP)
    The Observatorio del Teide (OT), in Izaña (Tenerife).
    The Observatorio del Roque de los Muchachos (ORM), in Garafía (La Palma).

    Roque de los Muchachos Observatory is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands, at an altitude of 2,396 m (7,861 ft)

    These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

    The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

    The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

    The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

    The IAC’s research programme includes astrophysical research and technological development projects.

    The IAC is also involved in researcher training, university teaching and outreachactivities.

    The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.



    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, SpainGran Telescopio CANARIAS, GTC

     
  • richardmitnick 11:17 am on May 25, 2017 Permalink | Reply
    Tags: , , , , Messier 87, , Weird energy beam seems to travel five times the speed of light   

    From New Scientist: “Weird energy beam seems to travel five times the speed of light” 

    NewScientist

    New Scientist

    22 May 2017
    Joshua Sokol

    1
    Trick of the light. NASA and The Hubble Heritage Team (STScI/AURA)

    Please welcome to the stage a master illusionist. An energy beam that stabs out of galaxy Messier 87 like a toothpick in a cocktail olive is pulling off the ultimate magic trick: seeming to move faster than the speed of light [always means speed of light in a vacuum].

    Almost five times faster, in fact, as measured by the Hubble Space Telescope.

    NASA/ESA Hubble Telescope

    This feat was first observed in 1995 in galaxy Messier 87, and has been seen in many other galaxies since. It might have you questioning your entire reality. Nothing can break the cosmic speed limit, right? You can’t just flaunt the laws of physics… can you?

    If you want to just enjoy the illusion from your seat in the audience, stop reading. Otherwise, I welcome you backstage for a look at how the trick works – and how it’s helping astronomers to understand the fate of entire galaxies.

    Blobs faster than light?

    We’ve known about the jet of plasma shooting from the core of Messier 87 since 1918, when astronomer Heber Curtis saw a ray of light connected to the galaxy. To be visible from so far away, it had to be huge – about 6000 light years long.

    As modern astronomers now know, pretty much all galaxies have a central black hole that periodically draws in stars and gas clouds.

    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    When gas begins to swirl down the drain, it heats up and magnetic fields focus some of it into jets of hot plasma. These jets shoot out at velocities near to – but not faster than – the speed of light.

    If you were to aim a telescope into the sky towards Messier 87, you would see that this lance of plasma is askew. Instead of pointing exactly into our line of sight, it’s angled a bit to the right.

    To understand the illusion, picture a single glowing blob of plasma starting at the base of this path and emitting a ray of light, both of which travel towards Earth. Now wait 10 years. In that time, the blob has moved closer at a sizeable fraction of the speed of light. That gives the rays emitted from that later position a few light years’ head start on the way to us.

    If you compare the first and second images from Earth’s perspective, it looks like the blob has just moved across the sky to the right. But because the second position is also closer to us, its light has had less far to travel than it appears. That means it seems to have arrived there faster than it actually did – as if the blob spent those 10 years travelling at ludicrous speed.

    One among many

    The jet from Messier 87 is more than just a curiosity, says Eileen Meyer at the University of Maryland, Baltimore County.

    All over the universe, outflows of energy from massive black holes can stop or start the formation of stars throughout galaxies. But it’s unclear how these outflows work and how much energy they contain.

    By appearing to move faster than light, jets such as the Messier 87 one change visibly over just a few years, which is unusual for distant objects like galaxies. That allows astronomers to make precise estimates of how fast the plasma is moving and thus how powerful the process is.

    Messier 87 is special because it is relatively close compared to other galaxies, making it easy to study. In 1999, astronomers used Hubble pictures of the jet taken over four years to see that plasma ripple outwards. In 2013, Meyer lengthened that to 13 years of images, which seemed to show that the plasma might also be moving in corkscrew-like spirals – as if it wasn’t complicated enough.

    Fresh results from Meyer, now being prepared for publication, extend that baseline again to a total of more than two decades and may offer new surprises. “Over 20 years, you know, things go bump in the night,” she says.

    And although the faster-than-light effect is old hat to her, she still stops to appreciate it sometimes. Most things we see travelling across the sky, such as planets and comets, are close to us. But Messier87 is tens of millions of light years away. “We can see, over a human lifetime, things moving,” she says. “Which is crazy.”

    See the full article here .

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